1. Field of the Invention
The present invention relates to a data storage apparatus comprising a data memory for storing a large number of data such as names and telephone numbers of persons, to read out desired data from the data memory and display the readout data on a display device.
2. Description of the Related Art
A conventional apparatus for storing a large number of data such as names and telephone numbers of persons in a memory, reading out desired data from the memory, and displaying the readout data on a display device is known, as described in U.S. Pat. Nos. 4,751,668 and 4,117,542. Along with the development of semiconductor techniques, the number of names and telephone numbers of persons to be stored in a memory is increasing to 50 and then 100.
When a phone call is made to a desired destination by using a conventional data storage apparatus of this type, a user causes the apparatus to search for a desired name and display the desired name. Available search methods are a method of alphabetically storing data in a memory and sequentially reading out data from the memory and displaying the readout data on the display every switch operation, as described in U.S. Pat. No. 4,751,668, and a method of inputting a full name or initials of a name of a person and directly displaying data corresponding to the input data, as described in U.S. Pat. No. 4,117,542. An auto-dialing apparatus is also known as described in U.S. Pat. No. 4,769,836, wherein a desired name of a person or subscriber and a telephone number are displayed, the displayed name and telephone number are checked, and an auto-dialing tones are generated to a handset upon switch operations.
In the apparatus for sequentially reading out names and telephone numbers whose data are stored in a memory, as described in U.S. Pat. No. 4,751,668, the names and telephone numbers of persons are sequentially displayed on a display unit upon switch operations. When a desired name and its corresponding telephone number are displayed, a user of the apparatus dials the telephone number. For example, 100 telephone number data are stored in the memory. If the user wants to make calls for 20 out of the 100 telephone numbers, the storage locations of the names of persons corresponding to these 20 telephone numbers are unknown. Therefore, since the names of 100 persons and the 100 telephone numbers must be sequentially displayed on the display unit upon switch operations, the switch operation becomes very troublesome.
When names of persons are directly input by key inputs, as described in U.S. Pat. No. 4,117,542, full names or initials of 20 persons must be input with keys, resulting in inconvenience. In addition, the apparatus of this type requires a keyboard for inputting names of persons and a complicated circuit means for reading out the same data as the input name data.
When the callee is out or the line is busy, a phone call is made for the next subscriber according to any one of the conventional methods described above. In this case, when the number of callees is large, the user is often confused of persons whose lines are busy and persons whose lines are not busy. Therefore, the user forgets to call again the person whose line has been busy or calls the same person twice.